Long Term Evolution-Advanced (LTE-A) is a further evolved and enhanced system of a 3GPP LTE system. In the LTE-A system, a carrier aggregation (CA) technology is introduced to meet a peak data rate requirement of International Telecommunication Union on the fourth generation communications technology. In carrier aggregation, spectrums of two or more component carriers (CC) are aggregated to obtain wider transmission bandwidth, where the spectrums of the component carriers may be adjacent continuous spectrums, or may be intra-band non-adjacent spectrums or even inter-band discontinuous spectrums. LTE-A user equipment can access, according to a capability and a service requirement of the LTE-A user equipment, multiple component carriers at the same time to send and receive data.
In a subsequent evolved LTE-A system, inter-base-station carrier aggregation, that is, dual connectivity (DC), is introduced. In this case, backhaul between base stations is non-ideal, and data cannot be transferred in real time between the base stations. In a DC scenario, two base stations may be asynchronous, that is, there is any time difference between start moments of downlink transmit subframes of the two base stations. Further, in this asynchronous DC scenario, multiple uplink channels that are sent by user equipment UE to two network side devices overlap. Specifically, referring to FIG. 1, a first channel overlaps a second channel and a third channel, where user equipment UE sends data to a secondary network side device SeNB over the first channel, and the user equipment sends data to a master network side device MeNB over the second channel and the third channel. An overlap portion exists between a first portion of a first subframe j in which the first channel is located and a second subframe i in which the second channel is located, and for ease of description, is referred to as a first overlap area. Further, an overlap portion exists between a second portion, other than the first portion, of the first subframe j and a third subframe i+1 in which the third channel is located, and for ease of description, is referred to as a second overlap area. The third subframe i+1 is a next subframe of the second subframe i, and the third subframe i+1 is used to send data to the master network side device.
In the asynchronous DC scenario in FIG. 1, a method for configuring power for all subframes in the prior art is: allocating power to the first subframe j and the second subframe i according to priorities of the first channel and the second channel, where all portions of the first subframe j are transmitted at equal power, that is, all symbols of the first subframe j are sent at equal power, and even though the second overlap area exists, the third subframe i+1 can be transmitted only at remaining power after allocation to the first subframe j.
For example, the first channel is a physical uplink control channel (PUCCH), and the second channel is a physical uplink shared channel (PUSCH). In existing power configuration, a priority of the PUCCH is higher than a priority of the PUSCH, so a channel priority of the first channel is higher than a channel priority of the second channel. Therefore, power is first allocated to the PUCCH in the first subframe j, and then power is allocated to the PUSCH in the second subframe i. According to the foregoing allocation method, if power of the first channel remains unchanged, even though the third channel is a PUCCH channel, that is, a priority of the third channel is higher than or equal to the priority of the first channel, only the remaining power can be allocated to the third channel in the third subframe i+1 because maximum transmit power of the UE is limited within one time segment. As a result, power allocated to the third subframe may not reach required power of the third frame, and transmission performance of the third subframe is affected.
However, in the foregoing scenario, when the UE is in a DC mode, the master network side device is responsible for sending and receiving of all radio resource control (RRC) control information of the UE, while the secondary network side device does not send or receive such information. Therefore, if types of uplink channels sent by the UE to the two network side devices or priorities of uplink control information carried in the uplink channels are the same, it is generally considered that an uplink channel sent to the master network side device is more important, and power should be preferentially allocated to this uplink channel.
Therefore, according to technical solutions in the prior art, although transmission at equal power in the first subframe j ensures correct reception of the first channel, when the priority of the third subframe i+1 is higher than the priority of the first subframe j, the third subframe i+1 to which enough transmit power should be preferentially allocated does not obtain corresponding transmit power, and consequently, power allocation to important information cannot be ensured in asynchronous DC.